In magnetic storage devices such as hard disk drives (HDD), read and write heads are used to magnetically write and read information to and from storage media, such as a magnetic storage disk. An HDD may include a rotary actuator, a suspension mounted on an arm of the rotary actuator, and a slider bonded to the suspension to form a head gimbal assembly. In a conventional HDD, the slider carries a write head and read head, and radially flies over the surface of the storage media. The magnetic media disk rotates on an axis, forming a hydrodynamic air bearing between an air bearing surface (ABS) of the slider and the surface of the magnetic media disk. The thickness of the air bearing at the location of the transducer is commonly referred to as “flying height.”
The read and write heads are mounted on a trailing edge surface of the slider, which is perpendicular to the air bearing surface (ABS). The magnetic media surface is exposed to the ABS during read and write operations. A Heat Assisted Magnetic Recording (HAMR) device or an Energy Assisted Magnetic Recording (EAMR) device is an enhanced HDD that applies heat to magnetically soften the media surface during recording, particularly useful for high capacity storage with physically smaller bit sizes. The heat may be generated by optical energy from a laser diode coupled to a waveguide, and focused by a near field transducer (NFT) formed on the slider. The NFT is arranged on or near the ABS to transit the focused optical energy to the magnetic media disk surface to produce the heating.